The present invention relates to a reclining angle adjustment device for adjusting the angle of inclination of the seat back of a reclining seat in a motor vehicle, i.e., the reclining angle of the reclining seat, and more particularly to a reclining angle adjustment device having lock mechanisms disposed respectively on the outer and inner sides of the reclining seat, each of the lock mecahnisms having rough and fine adjustment mechanisms.
There are known reclining angle adjustment devcies (see for example Japanese Patent Publication No. 57-11207) having a lock mechanism composed of a lower arm on which a pawl is angularly movably mounted and an upper arm on which an intermediate gear plate is mounted. By releasing the pawl from the intermediate gear plate with a release lever, the angle of inclination (or the reclining angle) of the upper arm pivotally coupled through an angularly movable shaft to the lower arm is roughly adjusted. The angular movement of a control handle attached to the lower arm is transmited to the upper arm through the angularly movable shaft and a planetary gear mechanism to effect fine adjustment of the reclining angle. Japanese Patent Publication No. 54-24167 discloses another reclining angle adjustment device having lock mechanisms disposed respectively on the outer and inner sides of a reclining seat. In the disclosed device, the angularly movable shaft of the planetary gear mechanism on the outer side of the reclining seat and the angularly movable shaft of the planetary gear mechanism on the inner side of the reclining seat are interconnected by a connecting lever for transmitting motion therebetween.
The angularly movable shafts are conventionally coupled to the connecting bar by constricted ends of square cross section of the connecting bar which are inserted respectively in square holes defined in the ends of the angularly movable shafts. It has been difficult to align the central axis of the intermediate portion of the connecting bar with the central axes of the square-shaped ends thereof. The central axes of the square-shaped ends of the connecting bar also tend to be misaligned. Therefore, difficulty has been encountered in smoothly transmitting the motion through the connecting bar.